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D型葡萄糖和L型葡萄糖的旋光性结构性能特点
来源:http://www.sspp8.com 日期:2019-06-12 发布人:admin
1. 葡萄糖的旋光性和开链构造式
1. Optical Rotation and Open Chain Constructions of Glucose
葡萄糖和绝大多数糖类均具有旋光性,可使平面偏振光发作旋转.若向右旋转,常用(+)表示,向左旋转,常用(-)来表示.
Glucose and most sugars have optical rotation, which can make the plane polarized light rotate. If it rotates to the right, it is usually expressed as (+) or left, and it is often expressed as (-).
【平面偏振光】
[Planar Polarized Light]
【有关偏振光与旋光性的材料】
[Material relating to polarized light and optical rotation]
构型:是指分子内部手性碳原子所连结的原子或基团在空间排布的相对位置.葡萄糖的分子式为C6H12O6.【 D-(+)-葡萄糖构造式】
Configuration: The relative position of the atoms or groups connected by chiral carbon atoms in a molecule. The molecular formula of glucose is C6H12O6. [D-(+) - glucose structure]
命名准绳:将-CHO的碳原子定为第一个碳原子,其它依次标示.从葡萄糖的开链构造式中能够看出C2、C3、C4、C5均为手性碳原子.由于在手性碳原子上衔接的原子或基团,它们在空间的位置是相对固定的,故写构造式时不能随意更动.如在葡萄糖分子中C3上的一OH在左边,C2、C4、C5上的一0H均在右边.
无水葡萄糖
Naming criterion: The carbon atom of -CHO is defined as the first carbon atom, and the others are labeled in turn. From the open-chain structure of glucose, we can see that C2, C3, C4 and C5 are all chiral carbon atoms. Because the atoms or groups connected on the chiral carbon atoms are relatively fixed in space, they can not be changed at will when writing the construction. For example, the OH on C3 in the glucose molecule is on the left, C2, C4. The 10H on C5 is on the right.
为了决议单糖的构型,能够甘油醛为规范.假如在投影式中,末了第2个碳原子(即己糖分子中的第5个碳原子)上的羟基在右边,与D-(+)-甘油醛相同,为D构型;羟基在左边,与L-(-)-甘油醛相同的为L构型.
In order to determine the configuration of monosaccharides, glyceraldehyde can be used as a standard. If in the projection formula, the hydroxyl group on the last second carbon atom (the fifth carbon atom in the hexose molecule) is on the right side, the same as D-(+)-glyceraldehyde, and the hydroxyl group is on the left side, the same as L-(-)-glyceraldehyde.
实考证明自然存在的葡萄糖为右旋,属于D构型,所以应写成D-(+)-葡萄糖.葡萄糖具有旋光性,其它大多数单糖分子也具旋光性.
It has been proved that the natural glucose is dextral and belongs to D configuration, so it should be written as D-(+) - glucose. Glucose has optical rotation, and most other monosaccharide molecules also have optical rotation.
2. 葡萄糖的环状平面构造式
2. The Ring Plane Formula of Glucose
由于碳原子的四个价键均匀散布于空间,因而葡萄糖的碳链实践上并不是一条直线.葡萄糖的C1上醛基的氧原子和C5上的羟基在空间位置比拟靠近,在分子内发作醛和醇的半缩醛反响,经过氧桥构成一个环状构造的半缩醛.葡萄糖分子内发作的半缩醛反响使第一碳原子也变成不对称碳原子,这个碳原子上的羟基称半缩醛羟基.半缩醛羟基在右边的称α-D-葡萄糖;半缩醛羟基在左边的称β-D-葡萄糖.葡萄糖的两种环状构造都是右旋的,故它们的全名分别称α-D-(+)-葡萄糖和β-D-(+)葡萄糖.
Since the four valence bonds of carbon atoms are evenly distributed in space, the carbon chain of glucose is not a straight line in practice. Oxygen atoms of aldehyde group on C1 and hydroxyl groups on C5 of glucose are comparatively close in space, and reactions of aldehydes and alcohols occur in molecules, forming a cyclic hemiacetal through oxygen bridge. The first carbon atom is also changed by reactions of aldehydes in glucose molecules. The hydroxyl groups on the carbon atoms are called semiacetal hydroxyl groups. The hydroxyl groups on the right side are called alpha-D-glucose; the hydroxyl groups on the left side are called beta-D-glucose. The two ring structures of glucose are dextral, so their full names are alpha-D-(+) -glucose and beta-D-(+) glucose, respectively.
【α-D-(+)-葡萄糖】 【D-(+)-葡萄糖】 【β-D-(+)葡萄糖】
[alpha-D-(+) -glucose] [D-(+) -glucose] [beta-D-(+) glucose]

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